Answer:
49x² + 42x + 9
Step-by-step explanation:
Given
(7x + 3)²
= (7x + 3)(7x + 3)
Each term in the second factor is multiplied by each term in the first factor, that is
7x(7x + 3) + 3(7x + 3) ← distribute both parenthesis
= 49x² + 21x + 21x + 9 ← collect like terms
= 49x² + 42x + 9
